The present invention relates to a microporous tape to be adhered to human skin by means of an adhesive layer harmless to the skin, providing the unique combination of both moisture-vapor permeability and hydrostatic-pressure resistance that, in effect, provides a liquid barrier. The tape is also weldable to a thermoplastic film. This product is highly suitable to be used as self-adhesive flange for stoma bags. Beside the use as a self-adhesive welding flange for stoma bags, the tape is also suitable for the use as surgical plaster. Due to its vapor permeability, no moist film will develop between the adhesive layer and the human skin which would result in a loss of adhesive qualities and an uncomfortable feeling for the person. In the use of the liquid barrier, mechanical qualities of the tape are maintained and a bacterial barrier is produced, so that the risk of exogenous bacterial infection to a plaster-covered wound is minimized.
Another application is the use of said tape adhered to human skin, including the optimal use of thermoplastic auxiliaries fused upon the non-adhered side such as for example an electrocardiogram electrode. The numerous kinds of commercially available stoma-bags for both colostomia- and ileostomia patients consist of a self-adhesive, flange which has as a function that the stoma bag can be attached to the stoma with a self-adhesive tape construction. Self-adhesive tapes are also commercially available, said tapes show a certain MVTR (moisture-vapor transmission rate), to allow constant breathing of the skin when covered with tape. However, this implies that an open construction is to be made which has a drawback that it is hardly or not moisture proof. In other words water from the outside contacting the tape, for example when the stoma patient with the stoma-bag adhered to the skin would take a shower or bath can penetrate tape and cause adhesive failure.
An internal market study of a number of European stoma bags' manufacturers showed that there is a demand for self-adhesive tape meeting the following requirements:
non-irritating pressure-sensitive adhesive, PA1 moisture vapor permeable woven or non-woven tape, PA1 moisture repellent non-adhered side, PA1 non-adhered side fusible by means of heat, PA1 and/or high frequency radio waves to a thermoplastic film, PA1 strong, i.e., hard to tear, but flexible product.
Due to the fact that the thermoplastic film can be welded to the non-adhered side of the tape, the stoma-bags manufacturer is in a position to produce the stoma bag in a more efficient and economical way.
Microporosity and moisture vapor permeability can be measured in various ways and a possibility is to measure the amount of air expressed in milliliters per minute (ml/min) by a known surface at a certain pressure. However, the most relevant and practice-based test, is measurement of the MVTR (moisture vapor permeability rate) expressed in grams of water per meter square per 24 hours (g H.sub.2 O/m.sup.2 /24 hr.) at 37.degree. C. The water-repellency may be measured by means of water retention in the web after its immersion. Another method to measure the water repellency is to measure the time up to leakage caused by a static liquid column of a specified height positioned on the tape.